B.1 Classes of Messages

The following lists classes of messages:

• Data Dependence (DD) on a statement indicates it could not be optimized because a data dependence involving the statement exists.

• Error (E) indicates a syntax error. These may include missing or extra characters, illegal keywords, or text in the wrong column. If a syntax error is encountered, KAP will not process the program unit, but will pass it to the compilable output unchanged. The listing file will indicate where the error is located. If a syntax error is encountered, the program should be corrected and rerun.

• Extension (EX) indicates where a construct in the original program is not allowed in the language KAP is producing. Some KAP products accept one form of Fortran, and produce another form. In some cases, an operation or type is allowed in the input language, but not in the output language. The statements containing these constructs will be marked as an extension.

• Informational (INF) points out where a condition exists that must be brought to the programmer's attention. Unreachable statements are an example.

• Inserted (I) indicates in the transformed listing where a statement has been inserted. In several of the transformations, statements must be inserted. These statements appear only in the transformed code.

• Inlining/IPA (INL) The subroutine or function called on this line was inlined or analyzed. If inlined, the CALL or reference has been replaced with the text of the routine. If analyzed, information about the routine is available for optimizing the code surrounding the CALL.

• Loop Reordering (LR) informs you that a Fortran statement is modified in the process of interchanging loops. KAP looks at outer loops in the process of optimizing a program. If an outer loop would be more efficient if innermost, and it is legal to reorder the loops, KAP will place the outer loop inside. In the process of doing this, KAP may have to change loop bounds (for triangular loops) or distribute loops or float IF assignments. These modifications are marked. Only the statements modified to do the exchange will be marked, not all statements in the exchanged loops.

• Miscellaneous (MIS) informs you that some KAP information has been lost. This does not mean the program has not been transformed properly, but that some messages generated in the process have been lost.

• Not Vectorized (NV) indicates that a statement was not vectorized because it has no vector version (for instance, an assigned GOTO or an I/O statement).

• Output Translation (OT) shows where constructs, which are valid in the input language but are not allowed in the output language (if different), were changed.

• Output Trans Fails (OTF) marks statements that have constructs that exist in the input language but are not representable in the output language (if different).

• Option Error (OW) tells you of a syntax error in a KAP directive or assertion. This error does not cause processing of a program unit to stop, but the directive or assertion is ignored. Please see Chapter 5 and Chapter 6 for the proper syntax for directives and assertions.

• Program Too Large (NO) tells you either that the program unit being processed is too large for KAP to optimize, or that the subprogram structure is too complex to maintain a calling tree. This class of message rarely appears.

• Question (Q) informs you that KAP attempted to optimize a loop nest, and in the process came across a data dependence it could not break at compile time without some knowledge not available to it. This knowledge may be available to you, so KAP will generate a question in the listing file. If you can answer the question by placing an assertion (see Chapter 6) before the loop the question referred to and rerunning the program, KAP may be able to optimize the loop.

  It should be noted that if the question is answered incorrectly, the transformation that KAP performs will be invalid, and may give incorrect answers.

• Scalar Optimization (SO) marks places in the transformed listing where a scalar loop optimization (such as loop unrolling) has been performed.

• Standardized (STD) marks where a program has been changed to improve the chances of finding optimizable code. The dusty deck transformations KAP performs use this notation. Examples of these are IF...GOTO to block IF, loop rerolling, and IF loop to DO loop conversion.

• Translator Error (TE) informs you of an internal KAP error. A notification is written to the error message file and a traceback is written to the listing file. The software vendor must be notified of this class of error so a correction can be made. If the code that causes the traceback can be sent along with the traceback, that will aid diagnosis. (If the error can be reproduced in a small program unit, that small program unit would be preferable to a large program.)

• Vector Enhanced (VE) informs you that transformations have been applied to this statement to improve optimization. KAP performs several transformations (such as forward substitution) intended to make the program easier to optimize. These transformations are not themselves major enhancements to the program, but allow other optimizations to work more effectively.

• Warning (W) are errors that are correctable. KAP found an illegal construct in the program, but the intent of the programmer is clear. If a syntax warning is encountered, KAP will still process the program unit. The listing file will indicate where the warning occurred.

Copyright © Digital Equipment Corporation. 1997. All Rights Reserved.